RESUMO
This study aimed to investigate the effect of age and genetics on the fecal microbiota of beef calves. Ten purebred Nellore (Bos taurus indicus) and ten crossbreed 50% Nellore-50% European breed (Bos taurus taurus) calves co-habiting on the same pasture paddock had fecal samples collected on days five (5 d), 14 d, 28 d, 60 d, 90 d, 180 d, 245 d (weaning) and 260 d after birth. All calves were kept with their mothers, and six Nellore dams were also sampled at weaning. Microbiota analysis was carried out by amplification of the V4 region of the 16S rRNA gene following high-throughput sequencing with a MiSeq Illumina platform. Results revealed that bacterial richness increased with age and became more similar to adults near weaning. Differences in microbiota membership between breeds were found at 60 d and 90 d and for structure at 60 d, 90 d, 245 d, and 260 d (p < 0.05). In addition, crossbreed calves presented less variability in their microbiota. In conclusion, the genetic composition significantly impacted the distal gut microbiota of calves co-habiting in the same environment, and further studies investigating food intake can reveal possible associations between microbiota composition and performance.
RESUMO
Several factors are known to affect the intestinal microbiota of cattle. However, how these changes occur over time is poorly understood. This study aimed to investigate the consequences of entrance into a feedlot and the effects of virginiamycin used as a growth promoter on the bovine fecal microbiota. Two batches of beef cattle (B1, n=50 and B2, n=36) entering a feedlot operation were randomly divided into two pens: one receiving virginiamycin and one group not receiving antibiotic (control group). Fecal samples were collected at arrival, mid feedlot and at exit to slaughter. The V4 region of 16S rRNA gene was amplified and sequenced. Escherichia coli strains isolated in samples from arrival and exit of B2 were also isolated and used as indicators of antimicrobial susceptibility. Marked changes in membership and structure of fecal microbiota occurred following entrance into the feedlot. At mid feedlot, virginiamycin affected bacterial community membership, but not structure, suggesting that the antibiotic had a stronger effect on the rare, but not on the most abundant species. The use of virginiamycin had no demonstrable effect on antibiotic resistance in E. coli. The differences found between batches are suggestive that variations in study conditions are important and can strongly affect the intestinal microbiota.
Assuntos
Antibacterianos/farmacologia , Bovinos/genética , Bovinos/microbiologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Fezes/microbiologia , Virginiamicina/farmacologia , Criação de Animais Domésticos/métodos , Animais , Brasil , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , Distribuição AleatóriaRESUMO
The objective of this experiment was to evaluate the effects of organic chromium supplementation on the body weight and weight gain of Nelore steers. Twenty calves were used, with initial weight of 179 kg and 6 months of age. They were distributed in two groups, being 10 animals per group. The experimental group received an organic chromium (1mg of carboaminofosfoquelato of chromium) per day. The mineral salt consumption was estimated for 50g/animal/day. The animals in the control group received the same mineral salt without chromium, in the same consumption. The mineral salt was furnished ad libitum and the animals were maintained in pickets with Brachiaria brizantha and B. decumbens pasture, with rotation during 348 days. For weight gain evaluation, the animals were weighed after 14 hours of solids and liquids fast, every 10 days in the first 40 days of the experiment. After this, steer weights were recorded at 28 days intervals. The organic Cr supplementation in Nelore steers there was influence (P 0.05) in the body weight it was on day 210, 258.2 kg and 252.28 kg for the organic chromium supplemented and for the control group, respectively.
O objetivo desse experimento foi avaliar o efeito da suplementação com cromo orgânico sobre o peso corporal e ganho de peso de bovinos da raça Nelore. Utilizaram-se 20 bezerros, inteiros, com peso inicial de 179 kg e 6 meses de idade, distribuídos ao acaso em dois tratamentos com 10 animais, sendo um grupo controle e outro suplementado com cromo orgânico (1mg de cromo na forma de carboaminofosfoquelato de cromo), veiculado em sal mineral com estimativa de consumo em torno de 50g/bezerro/dia. O lote controle recebeu o mesmo sal mineral sem o cromo, com a mesma estimativa de consumo. Ambos foram fornecidos ad libitum e os animais mantidos em piquetes de Brachiaria brizantha e B. decumbens, em forma de rodízio durante 348 dias. Para avaliação do ganho de peso, os animais foram pesados após 14 horas de jejum de alimentos sólidos e líquidos, a cada 10 dias nos primeiros 40 dias de experimento e após, a cada 28 dias. A suplementação com Cr orgânico em bovinos Nelore influenciou (P 0,05) o peso corporal aos 210 dias, sendo 258,2 kg e 252,28 Kg para o grupo suplementado com cromo orgânico e controle, respectivamente.
RESUMO
The objective of this experiment was to evaluate the effects of organic chromium supplementation on the body weight and weight gain of Nelore steers. Twenty calves were used, with initial weight of 179 kg and 6 months of age. They were distributed in two groups, being 10 animals per group. The experimental group received an organic chromium (1mg of carboaminofosfoquelato of chromium) per day. The mineral salt consumption was estimated for 50g/animal/day. The animals in the control group received the same mineral salt without chromium, in the same consumption. The mineral salt was furnished ad libitum and the animals were maintained in pickets with Brachiaria brizantha and B. decumbens pasture, with rotation during 348 days. For weight gain evaluation, the animals were weighed after 14 hours of solids and liquids fast, every 10 days in the first 40 days of the experiment. After this, steer weights were recorded at 28 days intervals. The organic Cr supplementation in Nelore steers there was influence (P 0.05) in the body weight it was on day 210, 258.2 kg and 252.28 kg for the organic chromium supplemented and for the control group, respectively.
O objetivo desse experimento foi avaliar o efeito da suplementação com cromo orgânico sobre o peso corporal e ganho de peso de bovinos da raça Nelore. Utilizaram-se 20 bezerros, inteiros, com peso inicial de 179 kg e 6 meses de idade, distribuídos ao acaso em dois tratamentos com 10 animais, sendo um grupo controle e outro suplementado com cromo orgânico (1mg de cromo na forma de carboaminofosfoquelato de cromo), veiculado em sal mineral com estimativa de consumo em torno de 50g/bezerro/dia. O lote controle recebeu o mesmo sal mineral sem o cromo, com a mesma estimativa de consumo. Ambos foram fornecidos ad libitum e os animais mantidos em piquetes de Brachiaria brizantha e B. decumbens, em forma de rodízio durante 348 dias. Para avaliação do ganho de peso, os animais foram pesados após 14 horas de jejum de alimentos sólidos e líquidos, a cada 10 dias nos primeiros 40 dias de experimento e após, a cada 28 dias. A suplementação com Cr orgânico em bovinos Nelore influenciou (P 0,05) o peso corporal aos 210 dias, sendo 258,2 kg e 252,28 Kg para o grupo suplementado com cromo orgânico e controle, respectivamente.